Accumulator



H. N. LOVE 2,805,684

ACCUMULATOR Sept 10, 1957 W W W W M q: wfl T 3% WM 5% mm. M m m m m Sept 10, 1957 H. N. LOVE 2,805,684

- I ACCUMULATOR Filed June 23, 1954 I 2 Sheets-Sheet 2 ENVEN'TQH V Cal by l YLW LUJJOVB ACCUMULATOR Harold Norris Love, Chicago, Ill., assignor to Ideal Roller and Manufacturing Company, Chicago, 111., a corporation of Illinois Application June 23, 1954, Serial N 0. 438,843

3 Claims. (Cl. 13830) This invention relates to accumulators of the type in which a rigid casing provides air and fluid spaces separated by a flexible partition diaphragm which flexes back and forth with changes in the relative pressures in the spaces due to the supply or withdrawal of fluid from one or the other of the spaces. In prior accumulators, this partition has taken the form either of a circular sheet or of a bag of rubber material secured to the interior of the tank in such a manner that it may, under certain conditions of service use, become ruptured due to excessive folding or elongation of the diaphragm material or rupture by rubbing against the interior of the tank.

The primary object of the present invention is to overcome the shortcomings of prior accumulators by a novel shaping of the air and liquid chambers and a novel mounting of the diaphragm separating the two chambers.

A more detailed object is to form the accumulator tank of generally toroidal internal cross-section with inner and outer wall portions of rounded or arcuate cross-section cooperating with a diaphragm of generally tubular form having two widely separated areas of attachment to the tank Wall.

Another object is to shape the diaphragm and the chamber walls so as to minimize the stretching of the diaphragm material as an incident to full collapse or expansion of the diaphragm.

Still another object is to provide an accumulator which, for a given volumetric capacity, will occupy less space than prior accumulators and this, without danger of rupturing the diaphragm under severe operating conditions.

A further object is to provide novel means for closing the liquid outlet valve in response to collapse of the diaphragm to a predetermined degree whereby to prevent extrusion of the diaphragm material into the outlet.

The invention also resides in the novel shaping of the air and liquid chambers and in location and construction of the air and liquid valves.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

Figure 1 is a diametrical sectional view of an ac- ,nited StatesPatent cumulator embodying the novel features of the present invention.

Fig. 2 is a cross sectional taken along the line 22 of Fig. 1.

Fig. 3 is a perspective view of the diaphragm.

Fig. 4 is an exploded view of the parts of the outlet valve. 1

Fig. 5 is a view similar to Fig. 2 showing the diaphragm fully collapsed.

Generally stated the improved accumulator as shown in the drawings by way of illustration comprises a rigid tank 10 having an air opening 11 and one or more liquid openings 12 and defining annular chambers 13 and 14 defined by walls of arcuate shape and separated by a tube-like diaphragm 15 which surrounds the axis 16 of HQC the chambers 13 and 14 and has two annular ends concentric with the axis 16 and secured to the tank around their entire peripheries.

In the preferred form shown, the tank comprises a thick walled generally circular casting 17 having flattened ends and cored out to provide an internal wall 18 which defines a recess 19 of generally toroidal shape. The

outer half portion 18 of the wall 18 is semi-circular in radial cross section while the inner half portion is of,

similar arcuate cross-sectional shape except that, for the purpose of reducing the overall diameter of the 'tank, the inner part of each radial section of the Wall intersects a corresponding part of the diametrically opposite section along a chord formed by the axis 16. Herein the inner part 18* of the wall 18 is interrupted short of the axis of the toroid so that opposite ends of the recesses 13 are defined by frusto conical projections 20 and 21 whose apices 22 are spaced apart along the axis 16. The projections 20 and 21 are formed as separate pieces projecting through holes 23 counterbored in opposite ends of the casting 17, the parts being clamped rigidly together by screws 24.

In the form shown in Fig. l, the diaphragm 15 which defines the inner wall of the outer chamber 14 and the outer wall of the inner chamber 13 is a molded cylindrical tube preferably composed of oil resistant rubber and corresponding in initial or unstretched axial length to the length of the toroidal recess 19. Opposite end portions of the tube fit closely around the prothe points of anchorage is, as shown in Fig. 1, substantially cylindrical when the chambers 13 and 14 are at the same pressure, this being the shape to which the tube is molded. The unsupported intermediate portion of the tube is thus free to expand or contract.

Usually, the outer chamber 14 contains air while the liquid to be delivered by the accumulator is contained in the inner chamber 13. Only one air opening 11 is required this being formed by a fitting 31 (Fig. 1) threaded into a hole in the outer peripheral portion of the tank 10 and enclosing the usual spring closed air check valve 30.

The combined liquid inlet and outlet 12 is substantially smaller in diameter than the ends of the diaphragm and extends through the projection 21 along the axis 16 thereof. Herein, the outlet comprises a passage 32 adapted for threaded connection with an external pipe 33 and is somewhat smaller at its inner end than the generally flat inner end of the frustum 21.

Extrusion of any part of the diaphragm into the passage when all of the liquid has been withdrawn from the tank and the diaphragm is fully collapsed is prevented eflectually by the action of a normally open valve which is disposed within the inner end portion of the passage 32 and is closed by the action of the diaphragm as the latter becomes fully collapsed. The liquid thus trapped" tion of the passage. This condition is normally maintained by a spring 37 between the bottom of the inverted cup and the rounded end 38 of a projection 39 upstanding from a disk 40.- The outer edge of the latter is clamped by a nut 41 against a shoulder 42. Thesurface 38 cooperates with a complemental surface 43 on the interior of the cup 34 to form the valve. When the cup is seated against the shoulder 36, the surfaces 38 and 43 are spaced apart as shown in Fig. 1 thus permitting the free flow of liquid in either direction through holes 44 in the disk and a hole 45 in the bottom of the cup. This condition of the valve obtains during normal operation of the accumulator.

The cup 34 projects a short distance beyond the end 22 of the cone 21 so asto be engaged by the diaphragm when substantially all of the liquid has been withdrawn from the tank chamber 13. If, at this time, any part of the collapsed diaphragm is bent across the end of the cone 21, the part. will engage the projecting end of the cup and, during further. withdrawal of the liquid will press the cup outwardly. As a result, the surface 43 will come against the projection 39 thus closing the valve. to present further escape of fluid from the tank. The liquid thus trapped within the cup thus blocks the hole 45 and effectually prevents any of the rubber material from being extruded into the tank outlet. Now, when fluid is again forced into the tank the pressure applied to the flanged end of the cup forces the latter inwardly thus opening the valve whose member 34 is then held in open position by the spring.

The accumulator constructed as above described is charged with air and liquid and used in the same manner as the devices now available commercially. When, during such use, enough liquid is withdrawn from the chamber 13 to collapse the diaphragm and move the cup 34 outwardly, the valves 38, 43 is thus closed preventing further escape of the liquid from the tank so as to eliminate any danger of damaging the diaphragm. by complete emptying of the chamber 13. To recharge the accumulator, oil is pumped into the tank through the pipe 33 and under sutficient pressure to overcome the prevailing pressure on the cup 34. As soon as the cup starts to move inwardly, the valve is opened and the oil forced directly into the chamber 13 will again expand the diaphragm.

It will be observed that the diaphragm is anchored to the tank wall around two widely spaced and continuous peripheral edges which surround the axis 16 and are at opposite ends of the diaphragm when the latter is of tubular form as shown in the drawings. As aresult, the diaphragm is held securely and against floating within the tank so that its shape and the manner of its flexing remain substantially the same irrespective of the position in which the axis of the tank is disposed in service use. The diaphragm expands and contracts by flexing of the rubber material between the two annular lines of anchorage and full expansion is accompanied by no more than about 50 percent elongation of the rubber. This is due to the rounded character of the toroidal recess and the arcuate shape of the rigid tank walls which limit the elongation of the rubber as the diaphragm expands and contracts.

This application is a continuation-in-part :of my application Serial No. 341,105, filed March 9, 1953 and now abandoned.

I :claim as my invention:

1. In an accumulator, thecombination of, a tank having an internal wall defining a recess in the form of a toroid, said wall terminating along the axis of the toroid in inwardly extending projections axially spaced apart at their inner ends, a tubular diaphragm of flexible material enclosing said projections within said recess, means securing the ends of said diaphragm to said projections whereby to divide said recess into inner and outer annular chambers, means controlling the fiow of liquid into and out of said inner chamber including a passage extending axially through one of said projections, a valve member slidable along said axis within said passage and having one end normally extending inwardly beyond the end of the projection for engagement by said diaphragm when the latter is collapsed, a seat within said passage cooperating with said member to form avalve which is closed by movement of the member by said diaphragm, and means urging said member inwardly to hold the valve normally open.

2. In an accumulator, the combination of, a tank having an internal wall defining a recess in the form of a toroid, said wall terminating along the axis of the toroid in inwardly extending projections axially spaced apart at their inner ends, a tubular diaphragm of flexible material enclosing said projectionswithin said recess, means securing the ends of said diaphragm to said projections whereby to dividesaid recess into inner and outer annual chambers, means controlling the flow of liquid into and out of said inner chamber including a passage extending axially through one of said projections, a cup slidable in the inner end of said passage with its bottom normally pro jecting inwardly beyond the end of the passage for engagement with said diaphragm, said bottom having a hole therethrough, a member disposed within said passage and cooperating with the open end of the cup around the interior thereof to form a valve, and means urging said cup. inwardly to maintain the valve open until the cup is forced outwardly by said diaphragm, said cup being forced inwardly to open the valve when liquid under pressure is delivered to. the outer end of said passage.

3. In an accumulator, the combination of, a tank havin an internal wall defining an annular recess in the form of a toroid, said wall terminating along the axis of the toroid in inwardly extending projections axially spaced at their inner ends whereby to leave the central portion of the toroid open, a tubular diaphragm of flexible material enclosing said projections and the toroid axis within said recess, means securing the ends of said diaphragm to said wall whereby to divide said recess into inner and outer annular chambers, means controlling the flow of fluid into said inner chamber including a passage extending axially through one of said projections, a valve member disposed within said passage and having a portion normally extending inwardly beyond the end of the projection for engagement by said diaphragm when the latter is collapsed, a seat within said passage cooperating with said member to form a valve which is closed by movement of the member by said diaphragm, and means urging said member inwardly to hold the valve normally open.

References Cited in the file of this patent UNITED STATES PATENTS Re. 20,887 Mercier Oct. 18, 1938 852,150 Whitney Apr. 30, l907 2,278,688 Caminez Apr. 7, 1942 2,290,337 Knauth July 21, 1942 2,385,016 Mercier Sept. 18, 1945 2,540,676 Johnson et al Feb. 6, 1951 2,583,231 Ragland Ian. 22, 1952 2,638,932 Alexander May 19, 1953 

